Monoesters of phosphonic acids



United States Patent Ofilice 3,350,479 MONOESTERS F PHGSPHONIC ACIDS Emile Cherbuliez and Joseph Rabinowitz, Geneva, Switzerland, assignors to Hooker Chemical Corporation, Niagara Falls, N.Y., a corporation of New York No Drawing. Filed Nov. 24, 1965, Ser. No. 509,648 8 Claims. (Cl. 260-956) This is a continuation-in-part of United States patent application Ser. No. 230,315, filed Oct. 11, 1962, now US. Patent No. 3,268,629.

The present invention relates to new phosphonic monoesters and to an improved process for making phosphonic monoesters. According to the invention, an alcohol is reacted with an anhydride of a phosphonic acid to produce phosphonic monoesters of high purity in very good yields.

As anhydrides of phosphonic acids there are preferably used those commonly known as phosphonic oxides. These anhydrides can be prepared by known methods, as for example, by the action of the dichloride of a phosphonic acid according to the equation:

in which R represents an aliphatic, aromatic or heterocyclic radical, usually of 1 to 18 carbon atoms, most often of 2 to carbon atoms; these radicals may be substituted, as for example, with a nitro group or a halogen atom, such as fluorine. The radical R may more especially be represented by a monocyclic aryl radial, such as the phenyl, halogeno-phenyl, e.g., p-fluorophenyl, p-chloro-phenyl, p-bromo-phenyl or nitro-phenyl, e.g., p-nitro-phenyl radical.

As a phosphonating agent, one may also use polyphosphonic acids, that is, the partial anhydrides of phosphonic which give a lesser yield of ester, but which permit the recovery, in the form of alkaline earth metal phosphonate, of the phosphonic acid which did not react and which may thus be used for another charge. The polyphosphonic acids are considered to be phosphonic anhydrides.

on corresponding dichlorides.

It is sufiicient to mix an equivalent of phosphonic oxide (R-PO with 0.5 to 3 moles, especially with 1.2 to 3 R OH alcohol reaction may also mixture becomes homogeneous and the phosphonic monoester is obtained, as exemplified by the following equation 7 the mixture in the form of its salt which may be characterized by the formula 335,4 Patented Oct. 31, 1967 as methyl or ethyl groups or aromatic or araliphatic radicals such as a phenyl or benzyl radical. These substituents may be found in any compatible position of the indicated radicals with respect to the OH to be phosphonated.

Thus, this reaction is a general one and applies to various alcohol types. If a polyol is treated by a phosphonic pentaerythritol, (hydroxymethyl)benzene, sorbitol and trimethylol propane. With the halogenated alcohols,

a secondary alcohol.

A preferred embodiment of this action of an alcohol acid in the presence alkylamine, e.g., cyclic tertiary base, equivalent of the to acid, such as a terpene alcohol.

If the radical R is the radical of an a-nitrilo alcohol, the nitrile group may be hydrolyzed to form an ester of tion of a cyclic derivative of the ester, which is easily hydrolyzed With water to form the monoester of the acarboxamido alcohol. With ,6-, and e-nitrilo alcohols the monoesters of the nitrilo alcohols are preferably obtained; the hydrolysis to the carboxamido derivative does not take place.

The monoesters obtained can be isolated as their metal salts. The alkaline or alkaline earth metal salts of phosn r) yhonic monoesters are practically neutral in aqueous soluzion (pH about 6) and can be preserved indefinitely in aqueous solution (at this pH the time of half-hydrolysis in a 0.1 molar aqueous solution of ester at 100 degrees centigrade is greater than 500 hours); the salts of phosphonic monoesters of amino alcohols are alkaline in aqueous solution (pH l0.511) and also are stable at this pH.

In order to isolate the alkaline earth metal or alkali metal salts of the phosphonic monoester, including the calcium, barium, strontium, sodium, potassium, lithium, aluminum and magnesium salts, one proceeds as follows:

After cooling, the excess alcohol is distilled (when a large excess is used) under vacuum. The residue is taken up by water and neutralized by a hydroxide of an alkaline earth metal to a pH of 8.2 (turning of phenolphthalein). (In the case of amino alcohols, it is desirable to add hydroxide sufficient to obtain a pH of about 11.) The phosphonic acid which may still be present (formed by hydrolysis of the oxide which may not have reacted, or formed in the course of the reaction when polyphosphonic acid is used) precipitates partially as an alkaline earth metal salt; it is completely precipitated by the addition of one volume of alcohol. This is filtered and the filtrate which contains the alkaline earth metal salt of the phosphonic monoester is evaporated and dried under vacuum. Generally, the product obtained is pure. If not, it is purified by extraction with boiling acetone (which dissolves the impurities); after cooling, the alkaline earth metal salt of the phosphonic monester is filtered.

If it is desired to obtain alkali metal salts of these monoesters, the alkaline earth metal salt is dissolved in water and there is added the required quantity of carbonate of an alkali metal. The precipitate of the alkaline earth metal carbonate formed is filtered off and the filtrate is evaporated to dryness under vacuum. The amorphous residue treated by acetone is transformed into a crystalline precipitate which is the alkali metal salt of the monoester. One may adapt the above methods to make other salts.

The alkaline earth metal salts of the phosphonic monoesters of superior aliphatic alcohols or of terpene alcohols are generally insoluble in water or in 50 percent ethyl alcohol. In order to isolate these monoesters, one proceeds preferably as follows:

(a) After cooling, the reaction mass is taken up by ether and neutralized by triethylamine. The triethylammonium salt of the phosphonic acid is filtered ofl, whereas the triethylammonium salt of the phosphonic monoester is soluble. The ether and the excess of the tertiary base are distilled, the residue is taken up by ether and the alkali earth metal salt of the phosphonic monoester is precipitated by adding an aqueous solution of the corresponding alkali earth metal halogenide. The precipitate is washed with water and is purified as previously described.

(b) If the reaction is carried out in the presence of a tertiary base such as trimethylamine, triethylamine or pyridine, the reaction mixture is taken up by ether and the phosphonate of the tertiary amine is filtered 01f. The ether and the excess of the tertiary base are distilled and the residue is taken up by water. The alkaline earth metal salt of the phosphonic monoester is precipitated by adding an aqueous solution of an alkali earth metal halogenide.

If the free phosphonic monoester crystallizes easily, the reaction mixture is taken up by water and the free phosphonic monoester is precipitated by adding a strong acid, such as hydrochloric acid (this is the case, for instance, of menthyl phenylphosphonic acid).

This new process of phosphonation of alcohols by phosphonic oxides and polyphosphonic acids has a number of advantages: it leads straight to monoesters only, it is simple and directly gives pure products in very high yield, calculated as a percentage of the theoretical value. Moreover, the process is quite general and many of the prepared phosphonic monoesters are new.

The monoesters thus obtained and their salts may be used as additives to liquid fuels, such as gasoline, or as products for impregnating fibers so as to make them fire-proof, pest-resistant or vermin-proof.

The invention is illustrated but not limited by the following examples. All parts are by weight and all temperatures are in degrees centrigrade, unless otherwise indicated.

EXAMPLE 1 140 parts (1 equivalent) of phenylphosphonic oxide (C l-I -PO and 48 to 64 parts (1.5 to 2 moles) of anhydrous methanol are heated to 100 degrees centigrade (bath temperature). After cooling, the excess alcohol is evaporated under vacuum and the residue is taken up with 500 to 860 parts of H 0. This solution is neutralized by Ca(OH) (or Ba(OH) if one desires to obtain a barium salt of the monoester) up to a pH at which phenolphthalein turns to colored form (about 8.2). Then an equal volume of alcohol is added and the calcium (or barium) phenylphosphonate thus precipitated is filtered. The filtrate, evaporated to dryness, yields the monomethylphenylphosphonate of calcium (or barium) which is generally pure initially. If it is not, the dry residue is dissolved in boiling acetone and, after cooling, the calcium or barium monomethylphenylphosphonate is filtered. The yield in pure product,

0 CH3 CH CH3 is 77 percent of theoretical.

Instead of phenylphosphonic oxide, other aryl phosphonic oxides may be employed to obtain corresponding salts of aryl phosphonic monoesters.

EXAMPLE 2 The phenylphosphonic monoesters (in the form of their calcium or barium salts) of the alcohols mentioned below have been prepared in the same manner as described in Example 1.

The monoester of ethanol of the formula:

(l)|/OM CeH5-P--O C2H5 Yield=84 percent.

The monoester of propanol of the formula:

0 OM ll CaHr-P-O CHrCHzCH;

Yield= percent.

The monoester of isopropanol of the formula:

H CaH 'P--O CH(CH3):

Yield-:56 percent.

The monoester of butanol of the formula:

ll/ ouHr-r -o 0 310111013105;

Yield:75 percent.

The monoester of isobutanol of the formula:

()l/OM oarr -r-o CH(CH3)-CH2CH3 Yield:60 percent.

The monoester of amyl alcohol of the formula:

(T/OM CaH5P--O CHzCHzCHgCHgCH;

Yield=71 percent.

In all the above formula M is Ca or Ba 5 EXAMPLE 3 The esters described in Examples 1 and 2 were also obtained with the aid of polyphenylphosphonic acid (rt-2) as the phosphonating agent, in the following manner:

In a flask connected to a water-jet pump and immersed in an oil bath, 140 parts (1 mole) of phenylphosphonic acid are heated gradually to 200 degrees centigrade (bath metal salt.

EXAMPLE 4 140 parts (1 equivalent) of phenylphosphonic oxide and 48 to 112 parts (1.5 to 2.0 moles) of propargyl OM CgHr- P O O CHr-CECH and the yield is 70 percent.-

By infrared spectroscopic examination, the presence of the -CEC group is verified.

In the same manner, there is prepared in 90 percent yield, phenylphosphonic monoester of allyl alcohol OM CflHPP-O o OH -CH=CHz All of these are new products. In the above formulas M=Ca or Ba EXAMPLE 5 140 parts (1 equivalent) of phenylphosphonic oxide and 120 to 161 parts (1.5 to 2.0 moles) of 2-chloro- (bath temperature). After cooling, the excess of chlorohydrin is distilled ofi under vacuum and one isolates the barium salt of the mono (Z-chloroethyl)phenylphosphonic acid,

/OH C5H5-P=0 0 CMgOHzCl in a yield of 85 percent.

In a similar manner, except for the temperature and duration of heating (which are shown in parenthesis), the

phosphonic monoesters of halogenated alcohols mentioned below are obtained, with yields indicated.

7 Yield=77 percent.

Phenylphosphonic monoester of 3 chloropropanol-l degrees centigrade, 16 hours) of the formula:

0 CHzCHzCHzCI Yield=84 percent.

Phenylphosphonic monoester of 4-chlorobutanol-1 (50 degrees centigrade, 16 hours) of the formula:

/OM CaH P=O O CHzCHzOHzCHzCl Yield=65 percent.

Phenylphosphonic monoester of 1,3-difluoropropanol-2 degrees centigrade, 48 hours) of the formula:

OOM

EXAMPLE 6 (bath temperature). There is isolated the calcium or barium salt of the (Z-hydroxyethyl-l)phenylphosphonic acid,

C6H5 P O CHZOHZOH in the manner described in Example 1 with a yield of 60 percent.

In a similar manner, except as it relates to the temperature for the tetramethyleneglycol, there are prepared W O H P-O OHzCHzCHzOH Yield-=65 percent. 7

The phenylphosphonic monoester of butanediol-1,4 (here the reaction takes place at SOIdegrees centigrade, for 48 hours) of the formula:

E) OM CaH51 O CHzOHzCHzCHzOH Yield=72 percent.

Phenylphosphonic monoester of pentanediol-l,5 of the formula:

OCHzOHzCHzCHzOHZOH In the case of butanediol-1,4 (tetramethyleneglycol), the temperature should not exceed 60 degrees centigrade, in order to avoid the formation of tetrahydrofurane in the phosphonation process.

Also, even if there is used a large excess of a phosphonating agent, only one group OH is phosphonated.

All of these esters are new.

In the formulas given M=Ca or Ba EXAMPLE 7 140 parts (1 equivalent) of phenylphosphonic oxide and 267 to 336 parts (3 to 4 moles) of dimethylcolamine (dimethylaminoethanol) are heated for 3 hours at 120 degrees centigrade. The excess of dimethylcolamine is distilled off under vacuum and the residue is dissolved in 800 to 1000 parts of water. There is then added an excess of calcium hydroxide in suspension in water with the mixture being agitated for several minutes. After filtering, one volume of alcohol is added to the filtrate to completely precipitate the calcium phenylphosphonate still present. This is followed by further filtration and evaporation under vacuum. An amorphous residue is obtained, which, after being treated with boiling acetone, cooled and filtered, yields a precipitate of calcium dimethylaminoethylphenylphosphonate. The formula of this compound is II CsHs-P O Cams 0 0 Cam ll Call -P which is pure. The yield is 30 percent.

EXAMPLE 8 140 parts (1 equivalent) of phenylphosphonic oxide and 152.5 (2.5 moles) of colamine are heated at 180 degrees centigrade (bath temperature) up to the point where the mass becomes homogenous. Then a vacuum is created in the flask, which is kept at this temperature overnight. After cooling, the reactive mass is dissolved in 800 to 1000 parts of water with the addition of an excess of calcium hydroxide. This mixture is agitated and an equal volume of ethanol is added. The liquid is filtered and evaporated dry under vacuum. The residue is treated with boiling alcohol and yields, after cooling, a precipitate of calcium (Z-aminoethyl)phenylphosphonate,

CaHs-P O CHrCHzNHa in 40 percent yield.

EXAMPLE 9 140 parts (1 equivalent) of phenylphosphonic oxide, 79 parts (1 mole) of pyridine and 111 to 148 parts (1.5 to 2.0 moles) of tertiary butanol are heated for one night at 75 degrees centigrade (bath temperature). A calcium or barium salt of t-butylphenylphosphonic acid,

O C -sh 7 tained EXAMPLE 10 One mole of cetylic alcohol and one equivalent of phenylphosphonic oxide are heated for 48 hours at 110 degrees centigrade. After cooling, the reaction mixture is taken up by ether and four equivalents of triethylamine are added. The precipitate of triethylammonium phenylphosphonate is filtered off, whereas the triethylammonium salt of the monoester is soluble. The ether and excess of triethylamine are evaporated under reduced pressure and the residue is taken up by ether. This solution, treated with aqueous barium chloride, yields a gelatinous precipitate which is filtered off, washed with water and then with acetone and ether, and finally dried in vacuum over P 0 The yield is 50 percent of pure barium cetyl phenylphosphonate:

O 0 Bars Calls-P O CH2(CH2)14CH3 and when using the described procedure, the following barium phenylphosphonic monoesters are obtained:

0 OBao.5 .1-1. i

O CH2(CH2)CH3 Yield=55 percent.

CsH5-P O GH2(OH2)8CH3 Yield==23 percent.

C H 'P o CHz(CF7) CHFz Yield=55 percent.

EXAMPLE 11 One mole of nerol, two moles of triethylamine and one equivalent of phenylphosphonic oxide are mixed carefully (the reaction is exothermic and it is necessary to cool). After a few minutes the mixture becomes hom-ogenous. It is then heated at degrees centigrade for 15 hours (with good agitation). After cooling, the reaction mass is taken up by anhydrous ether. The triethylammonium phenylphosphonate is filtered off and the ether and the excess of triethylamine are evaporated under reduced pressure. The oily residue is dissolved in water and the pH brought to about 5, by adding dilute hydrochloric acid. When an excess of a concentrated aqueous solution of calcium chloride is added to the preceding solution, voluminous precipitate of the calcium salt of the phenylphosphonic monoester appears. This precipitate, which retains most of the unreacted terpene alcohol, is washed with water and then with acetone which dissolves most of the retained alcohol. To achieve the elimination of the retained alcohol, the precipitate is finally washed with ether and then dried in vacuo over P 0 The yield is 30 percent of pure calcium neryl phenylphosphonate In a similar manner, the calcium salts of the phenylphosphonic monoesters of geraniol and farnesol are 0bin 31 percent yield each.

9 EXAMPLE 12 is then heated for 15 hours at 70-75 the reaction mixture iezs 's obtained in an 81 percent yield.

In a similar manner, bornyl phenylphosphonic acid, C H O' P, melting point 104-10 degrees centigrade, is prepared from borneol in an 88 percent yield.

EXAMPLE 13 One mole of lactonitrile and one phosphonic oxide are heated at 90 degrees centigrade for 46 hours. After cooling, the reaction mass is taken up by cold water and is quickly neutralized by barium hydroxide to a pH of 8.2 (turning of phenolphthalein). One volume of cold alcohol is then added to complete the 'preequivalent of phenyl- (70 per-cent); NCCH(CH )CH OH '(34 percent); NC-CH CH CH OH (58 percent);

(59 percent). The first two nitrilo alcohols yield the corresponding carboxamidoalkyl phenylphosphonic monoesters and the other nitrilo alcohols (B-, 'yand fi-nitrilo corresponding nitriloalkyl phenyl- EXAMPLE 14 One mole of anhydrous glycerol and one mole of phenylphosphonic oxide are heated at 165 degrees centiminutes with absolute alcohol. After cooling, one volume of acetone is added and the precipitate filtered off, washed with alcohol and vacuum dried. These operations are repeated on this product until pure barium glyceryl phenylphosphonate is obtained. The yield is 49 percent.

HOCH CHOHCH OP(O) (C H OBa barium a-glyceryl phenylphosphonate HOCH CH[OP(O) (C -H O a0,5) lCH OH:

barium ,B-glyceryl phenylphosphonate.

The determination of the neighboring OH groups by the method of Malaprade indicates that the product is composed of 51.5 percent of barium a-glyceryl phenylphosphonate and of 48.5 percent of the ,B-derivative.

EXAMPLE 15 Six moles of tribromoethanol and 4 equivalents of phenylphosphonic oxide are heated at 90 degrees centibromoethyl phenylphosphonate having the following formula:

CBr CH OP( O) (C H OBa Yield: percent In a similar manner are prepared the phenylphosphonic monoesters of trichloroethanol, trichloroisopropanol and trifluoroethanol:

CCI CH OP(O) (C H (OBa Yield: 88 percent CF CH OP(O)'(C H )(OBa Yield: 81 percent EXAMPLE 16 In a similar manner as described in Examples 1 to 15, p-fluorop enylphosphonic monoesters are obtained in for example, as starting alcohols: methanol, 1:- butanol, t-amyl alcohol, propane-1,3-diol, 2-chloro-1- ethanol, n-decanol, 2-amino-l-ethanol, Z-dimethylaminol-ethanol, lactonitrile and Z-nitrilo-l-ethanol, the following p-fiuorophenylphosphonic monoesters are obtained:

R-P(O)(OM)(OCH3) (70%); 3)3 )(R)(O 2 5)( 3) HOCHZCHZCHZOHO) (R) (OM) 70%) cicr-r crr omo) (R) (OM) (62%); 3( 2)8 2 H2NCH2CH2OP(O) (R) (0M) (53 (CH3)2NCH2CH2OP(O)(R)(OM) 30%); H2N-COCH(CH3)OP(O)(R)(OM) (38%); NC CH2CH2OP(O) R 0M) (64% R represents the p-fluorophenyl radical (FC H M represents an equivalent of an alkali earth metal and the yield is indicated in parenthesis.

p-Fluorophenylphosphonic oxide reacts with all the other alcohols mentioned in Example 1 to 15 to yield the corresponding p-fiuorophenyl phosphonic monoesters.

The p-fluorophenylphosphonic oxide is prepared as follows according to the equation:

38 grams (0.216 mole) of p-fiuorophenylphosphonic cid and 64 grams (0.3 mole) of p-fluorophenylphos- \honyl dichloride are heated at 200 degrees centigrade for wo hours (under light vacuum in order to facilitate the limination of the hydrochloric gas evolved during the 'eaction). The excess of dichloride is distilled under reluced pressure. After cooling, the residue is heated with 100 milliliters of dry benzene until complete dissolution. This solution is left for two days at 5 degrees centigrade and the precipitate (p-fiuorophenylphosphonic oxide) filtered off. The filtrate is left again for two days at 5 degrees Centigrade and a second amount of 'p-fluorophenylphosphonic oxide is filtered off. The operation is repeated until no further precipitation occurs (after concentration of the solution to 200 milliliters). The precipitates are washed with benzene and dried in vacuo at 60 degrees Centigrade. In this manner, 60 grams of pure p-fiuorophenylphosphonic oxide, melting point 109-111 degrees centigrade, are obtained (yield 88 percent).

(C H O FP) Calculated: F, 12.0 percent; P, 19.6 percent; equivalent weight, 158.1. Found: F, 12.4 percent; P, 193 percent, equivalent weight, 160.

What is claimed is:

1. A compound selected from the group consisting of compounds represented by the formulas wherein R is selected from the group consisting of phenyl, halogeno-phenyl and nitro-phenyl, R is selected from the group consisting of alkadienes and alkatrienes of up to 18 carbon atoms, and M is selected from the group consisting of alkali metals and alkaline earth metals.

2. A compound in accordance with claim 1 of the formula OH R-P O wherein R and R are each as defined in claim 1.

12 3. A compound in accordance with claim 1 of the formula wherein R and R are each as defined in claim 1.

4. A compound in accordance with claim 3 wherein R is selected from the group consisting of phenyl and pfluorophenyl.

5. A compound according to claim 2, in which R is selected from the group consisting of phenyl and p-fiuorophenyl.

6. Farnesyl phenylphosphonate of the formula:

/OH C@H5P=O OClix-CH CCHz-CHzCH=C-CHr-CHz-CH=CCH3 H H; on;

7. Neryl phenylphosphonate of the formula:

/OH CeH5P=O OCHr-CH=(IJCHz-CH2CH=$CH3 CH3 CH;

8. Geranyl phenylphosphonate of the formula:

/OH C5H5--P=O 3 OCHz-CH=OCHz-CH CH=C-CH; z

References Cited UNITED STATES PATENTS 2,792,374 5/1957 Bradley et a1. 260-961 X CHARLES B. PARKER, Primary Examiner. R. L. RAYMOND, Assistant Examiner. 

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF COMPOUNDS REPRESENTED BY THE FORMULAS 